JP2019138412A - Robot and gear unit - Google Patents

Abstract

To provide a robot capable of reducing the cost of a gear unit, and the gear unit.SOLUTION: A gear unit comprises: an internal gear; a flexible external gear that partially meshes with the internal gear and rotates relative to the internal gear around a rotational axis; and a wave generator that contacts with an inner peripheral surface of the external gear and moves a meshing position of the internal gear and the external gear in a circumferential direction around the rotational axis. The internal gear is characterized in that in a cross-sectional view cut along a plane including the rotational axis, a virtual straight line obtained by extending a tooth trace of the internal gear intersects the rotational axis.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a robot and a gear device.

  In a robot including a robot arm configured to include at least one arm, for example, a joint portion of the robot arm is driven by a motor. In general, rotation of the driving force from the motor is reduced by a gear device (reduction gear). To be done. As such a gear device, for example, a wave gear device as disclosed in Patent Document 1 is known.

  The wave gear device described in Patent Literature 1 includes an annular rigid internal gear, a flexible external gear arranged inside the rigid internal gear, and an elliptical contour fitted inside the flexible external gear. And a wave generator. Here, the rigid internal gear and the flexible external gear have a difference in the number of teeth, and the flexible external gear is bent elliptically by a wave generator, and both ends of the elliptical long axis direction. Meshes with the rigid internal gear. When the wave generator is rotated, the meshing position of the rigid internal gear and the flexible external gear moves in the circumferential direction, and the rigid internal gear and the flexible external gear rotate relative to each other according to the difference in the number of teeth. .

JP 2012-251588 A

  In the wave gear device described in Patent Document 1, since the respective streak directions of the rigid internal gear and the flexible external gear are parallel to the rotation axes of both gears, only the dimensional accuracy of both gears and the wave generator is provided. The tooth contact strength of both gears is determined by the above. Therefore, in the wave gear device described in Patent Document 1, high dimensional accuracy is required for both gears and the wave generator, and as a result, it is difficult to reduce the cost of the wave gear device.

A robot according to an application example of the present invention includes a first member,
A second member that rotates relative to the first member;
A gear device that transmits a driving force for rotating the second member relative to the first member from one side to the other side of the first member and the second member;
The gear device is
An internal gear,
A flexible external gear that partially meshes with the internal gear and rotates relative to the internal gear around a rotation axis;
A wave generator that contacts an inner peripheral surface of the external gear, and moves a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis;
One of the internal gear, the external gear and the wave generator is connected to the first member, and the other is connected to the second member.
In a cross-sectional view cut along a plane including the rotation axis, a virtual straight line obtained by extending the tooth trace of the internal gear intersects the rotation axis.

It is a side view showing a schematic structure of a robot concerning an embodiment of the present invention. It is a disassembled perspective view which shows the gear apparatus which concerns on 1st Embodiment of this invention. FIG. 3 is a front view of the gear device shown in FIG. 2 (viewed from the direction of the axis a). FIG. 3 is a sectional view schematically showing the gear device shown in FIG. 2 (a view cut along a plane including an axis a). It is a figure which shows typically the state of the outer peripheral surface of the wave generator in the gear apparatus shown in FIG. 2, and the internal peripheral surface of the external gear in a natural state. FIG. 3 is an enlarged cross-sectional view for explaining adjustment of the position of an internal gear in the direction of the axis a in the gear device shown in FIG. 2. It is sectional drawing (figure cut along the plane containing axis line a) which shows the conventional gear apparatus typically. It is sectional drawing (figure cut along the plane containing the axis line a) which shows typically the gear apparatus which concerns on 2nd Embodiment of this invention.

  Hereinafter, a robot and a gear device of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

1. Robot FIG. 1 is a side view showing a schematic configuration of a robot according to an embodiment of the present invention. Hereinafter, for convenience of explanation, the upper side in FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”. Further, the base side in FIG. 1 is referred to as “base end side”, and the opposite side (end effector side) is referred to as “tip side”. Further, the vertical direction in FIG. 1 is defined as “vertical direction”, and the horizontal direction is defined as “horizontal direction”.

  A robot 100 shown in FIG. 1 is, for example, a robot used for operations such as feeding, removing, transporting, and assembling precision instruments and parts (objects) constituting the precision equipment. As shown in FIG. 1, the robot 100 includes a base 110, a first arm 120, a second arm 130, a work head 140, an end effector 150, and a wiring routing unit 160. . Hereinafter, each part of the robot 100 will be briefly described.

  The base 110 is fixed to a floor surface (not shown) with bolts or the like, for example. A control device 190 that performs overall control of the robot 100 is installed inside the base 110. In addition, a first arm 120 is connected to the base 110 so as to be rotatable around a first axis J <b> 1 (rotating axis) along the vertical direction with respect to the base 110.

  Here, a first drive unit 170 is installed in the base 110. The first driving unit 170 includes a motor 171 that is a first motor such as a servo motor that generates a driving force that rotates the first arm 120, and a gear that is a first speed reducer that reduces the rotation of the driving force of the motor 171. Device 1. The input shaft of the gear device 1 is connected to the rotation shaft of the motor 171, and the output shaft of the gear device 1 is connected to the first arm 120. Therefore, when the motor 171 is driven and the driving force is transmitted to the first arm 120 via the gear device 1, the first arm 120 rotates around the first axis J1 in the horizontal plane.

  A second arm 130 is connected to the distal end portion of the first arm 120 so as to be rotatable about a second axis J2 (rotating axis) along the vertical direction with respect to the first arm 120. Although not shown, a second driving unit is set in the second arm 130. The second drive unit includes a second motor that generates a driving force that rotates the second arm 130, and a second speed reducer that decelerates the rotation of the driving force of the second motor. Then, when the driving force of the second motor is transmitted to the second arm 130 via the second reduction gear, the second arm 130 rotates in the horizontal plane around the second axis J2 with respect to the first arm 120. To do.

  A work head 140 is disposed at the tip of the second arm 130. The working head 140 has a spline shaft 141 inserted through a spline nut and a ball screw nut (both not shown) arranged coaxially at the tip of the second arm 130. The spline shaft 141 can rotate around the axis J3 with respect to the second arm 130 and can move (elevate) in the vertical direction.

  Although not shown, a rotation motor and a lifting motor are disposed in the second arm 130. The driving force of the rotary motor is transmitted to the spline nut by a driving force transmission mechanism (not shown), and when the spline nut rotates forward and backward, the spline shaft 141 rotates forward and backward about the axis J3 along the vertical direction.

  On the other hand, the driving force of the lifting motor is transmitted to the ball screw nut by a driving force transmission mechanism (not shown), and when the ball screw nut rotates forward and backward, the spline shaft 141 moves up and down.

  An end effector 150 is connected to the tip (lower end) of the spline shaft 141. The end effector 150 is not particularly limited, and examples thereof include an object that grips the object to be conveyed and an object that processes the object to be processed.

  A plurality of wires connected to each electronic component (for example, a second motor, a rotary motor, a lifting motor, etc.) arranged in the second arm 130 are tubular wires that connect the second arm 130 and the base 110. It is routed into the base 110 through the routing unit 160. Further, the plurality of wirings are collected in the base 110, and are routed to the control device 190 installed in the base 110 together with wirings connected to the motor 171 and an encoder (not shown).

  The robot 100 as described above includes a base 110 that is a first member, a first arm 120 that is a second member that rotates with respect to the base 110, and the first arm 120 that rotates with respect to the base 110. And a gear device 1 that transmits the driving force to be moved from one side of the base 110 and the first arm 120 to the other side. It can be said that the structure including the first arm 120 and the second arm 130 is a “second member”. Further, the “second member” may include the end effector 150. “Rotation” includes moving in one direction with respect to a certain center point or in both directions including the opposite direction, and rotating with respect to a certain center point.

2. Gear device <First embodiment>
FIG. 2 is an exploded perspective view showing the gear device according to the first embodiment of the present invention. 3 is a front view of the gear device shown in FIG. 2 (viewed from the direction of the axis a). FIG. 4 is a cross-sectional view schematically showing the gear device shown in FIG. 2 (a view cut along a plane including the axis a). FIG. 5 is a diagram schematically showing the state of the outer peripheral surface of the wave generator and the inner peripheral surface of the external gear in the natural state in the gear device shown in FIG. 2. FIG. 6 is an enlarged cross-sectional view for explaining the adjustment of the position of the internal gear in the direction of the axis a in the gear device shown in FIG. FIG. 7 is a cross-sectional view (a view taken along a plane including the axis a) schematically showing a conventional gear device. In each drawing, for convenience of explanation, the dimensions of the respective parts are appropriately exaggerated as necessary, and the dimensional ratio between the respective parts does not necessarily match the actual dimensional ratio.

  A gear device 1 shown in FIGS. 2 to 4 is a wave gear device, and is used, for example, as a speed reducer. The gear device 1 includes an internal gear 2, a cup-type external gear 3 disposed inside the internal gear 2, and a wave generator 4 disposed inside the external gear 3. Have. Although not shown, a lubricant such as grease is appropriately disposed in each part of the gear device 1 as necessary.

  Here, one of the internal gear 2, the external gear 3, and the wave generator 4 is connected to the base 110 (first member) of the robot 100 described above, and the other is connected to the robot 100 described above. It is connected to the first arm 120 (second member). In the present embodiment, the internal gear 2 is fixed to the base 111 (first member), the external gear 3 is connected to the first arm 121 (second member), and the wave generator 4 is described above. Connected to the rotation axis of the motor 171 of the robot 100. In the present embodiment, as shown in FIG. 4, the internal gear 2 is connected to the member 6 via the spacer 7, and the member 6 is the base 110 or is attached to the base 110. It is a connected (fixed) member.

  When the rotating shaft of the motor 171 rotates, the wave generator 4 rotates at the same rotational speed as the rotating shaft of the motor 171. Since the internal gear 2 and the external gear 3 have different numbers of teeth, the meshing positions of the internal gear 2 and the external gear 3 move relative to each other around the axis a (rotation axis) due to the difference in the number of teeth. Rotate. In the present embodiment, since the number of teeth of the internal gear 2 is larger than the number of teeth of the external gear 3, the external gear 3 can be rotated at a rotational speed lower than the rotational speed of the rotating shaft of the motor 171. . That is, it is possible to realize a reduction gear having the wave generator 4 on the input shaft side and the external gear 3 on the output shaft side.

  In addition, the connection form of the internal gear 2, the external gear 3, and the wave generator 4 is not limited to the form mentioned above, For example, the external gear 3 is fixed with respect to the base 111, and the internal gear 2 is fixed. Even if connected to the first arm 121, the gear device 1 can be used as a speed reducer. Further, even if the external gear 3 is connected to the rotation shaft of the motor 171, the gear device 1 can be used as a speed reducer. In this case, the wave generator 4 is fixed to the base 111, and the internal gear. 2 may be connected to the first arm 121. When the gear device 1 is used as a speed increasing device, that is, when the external gear 3 is rotated at a rotational speed higher than the rotational speed of the rotating shaft of the motor 171, the input side (motor 171 side) and the output side described above are used. The relationship with the (first arm 121 side) may be reversed.

  In such a gear device 1, as shown in FIG. 4, in a cross-sectional view cut along a plane including the axis a, a virtual streak of the internal gear 2 is extended (the root of the internal tooth 23 is extended). The straight line b is not parallel to the axis a, and intersects the axis a at a position P. Thereby, by adjusting the relative position of the internal gear 2 and the external gear 3 in the direction along the axis a, the tooth contact strength between the internal gear 2 and the external gear 3 is adjusted. Can do. Therefore, good meshing between the internal gear 2 and the external gear 3 can be realized without excessively increasing the dimensional accuracy of the internal gear 2, the external gear 3, and the wave generator 4. Hereinafter, each part of the gear device 1 will be described.

  As shown in FIGS. 2 to 4, the internal gear 2 is a ring-shaped rigid gear having an internal tooth 23 and configured by a rigid body that does not substantially bend in the radial direction.

  As shown in FIG. 4, the streak direction of the internal teeth 23 is inclined with respect to the axis a. Therefore, in a cross-sectional view cut along a plane including the axis a, a virtual straight line obtained by extending the teeth of the internal gear 2 intersects the axis a at the position P. In the present embodiment, the tooth line direction of the internal gear 2 is inclined with respect to the axis a so that the inner diameter of the internal gear 2 decreases from the right side to the left side in FIG. Therefore, the position P is closer to the bottom 32 (the other end) than the center C of the tooth width of the internal gear 2. The internal teeth 23 may be spur gears or helical gears. In any case, the straight line b intersects the axis a in a cross-sectional view cut along a plane including the axis a.

  Here, the internal gear 2 is connected to the base 110 (first member), and a spacer 7 is provided between the internal gear 2 and the member 6 or the base 110 (first member). Is arranged. By changing the thickness of the spacer 7 arranged in this way, the relative position of the internal gear 2 and the external gear 3 in the direction along the axis a can be easily changed. The constituent material of the member 6 is, for example, a metal material or the like, and may be the same as or different from the constituent material of the base 110.

  The spacer 7 is, for example, a plate-like or sheet-like member, and regulates the distance between the internal gear 2 and the member 6 according to the thickness of the spacer 7. The constituent material of the spacer 7 is not particularly limited, and examples thereof include a resin material, a metal material, and a ceramic material. Especially, it is preferable to use a metal material or a ceramic material from a viewpoint of reducing the fluctuation | variation of the distance between the internal gear 2 and the member 6. FIG. In addition, the spacer 7 may be comprised with the single material and may be comprised with the composite material. The spacer 7 may be an adhesive containing a gap material.

  If a plurality of spacers 7 having different thicknesses are prepared, the spacer 7 arranged between the internal gear 2 and the member 6 is replaced with a spacer 7 having a different thickness, for example, a two-dot chain line in FIG. As can be seen, the relative positions of the internal gear 2 and the external gear 3 in the direction along the axis a can be changed. The spacer 7 may be composed of a plurality of members, and the internal gear 2 and the external gear 3 can be changed by changing the number of the members disposed between the internal gear 2 and the member 6. The relative position in the direction along the axis a can also be changed. Note that the spacer 7 may not be disposed between the internal gear 2 and the member 6, and in this case, the distance between the internal gear 2 and the member 6 is the shortest.

  Here, a method for fixing the internal gear 2 and the member 6 is not particularly limited, and examples thereof include screwing. When the fixing method of the internal gear 2 and the member 6 is screwing, the spacer 7 may be fastened together with the internal gear 2 and the member 6 and is disposed between the internal gear 2 and the member 6. When the spacer 7 is exchanged, etc., the screw for fixing the internal gear 2 and the member 6 may be loosened and removed if necessary.

  The external gear 3 is inserted inside the internal gear 2. The external gear 3 is a flexible gear that has external teeth 33 (teeth) that mesh with the internal teeth 23 of the internal gear 2 and can bend and deform in the radial direction. Further, the number of teeth of the external gear 3 is smaller than the number of teeth of the internal gear 2. Thus, the reduction gear can be realized by the number of teeth of the external gear 3 and the internal gear 2 being different from each other.

  In the present embodiment, the external gear 3 has a cup shape, and external teeth 33 are formed on the outer peripheral surface thereof. Here, the external gear 3 has a cylindrical barrel portion 31 with one end portion (right end portion in FIG. 4) opened, and a radial direction from the other end portion (left end portion in FIG. 4) of the barrel portion 31. And a bottom portion 32 that is an attachment portion extending radially inward in the present embodiment. The body portion 31 has external teeth 33 that are centered on the axis a and mesh with the internal gear 2. An output side shaft body (for example, a rotating shaft of the motor 171) is attached to the bottom portion 32 by screwing or the like.

  As shown in FIG. 3, the wave generator 4 is disposed inside the external gear 3 and is rotatable about the axis a. The wave generator 4 deforms the outer teeth 33 into the inner teeth 23 of the internal gear 2 by deforming the cross section of the body 31 of the external gear 3 into an elliptical shape or an oval shape having the major axis La and the minor axis Lb. Bite into. Here, the external gear 3 and the internal gear 2 are engaged with each other inside and outside so as to be rotatable around the same axis a.

  In the present embodiment, the wave generator 4 includes a cam 41 and a bearing 42 attached to the outer periphery of the cam 41. The cam 41 includes a shaft portion 411 that rotates around the axis line a, and a cam portion 412 that protrudes outward from one end portion of the shaft portion 411. Here, the outer peripheral surface of the cam portion 412 has an elliptical shape or an oval shape having the major axis La in the vertical direction in FIG. 3 when viewed from the direction along the axis a. The bearing 42 includes a flexible inner ring 421 and an outer ring 423, and a plurality of balls 422 disposed therebetween.

  As shown in FIG. 4, the inner ring 421 is fitted into the outer peripheral surface of the cam portion 412 of the cam 41 and is elastically deformed into an elliptical shape or an oval shape along the outer peripheral surface of the cam portion 412. Accordingly, the outer ring 423 is also elastically deformed into an elliptical shape or an oval shape. The outer peripheral surface 424 of the outer ring 423 is in contact with the inner peripheral surface 311 of the body portion 31. In addition, the outer peripheral surface of the inner ring 421 and the inner peripheral surface of the outer ring 423 are raceways that cause the plurality of balls 422 to roll while being guided along the circumferential direction. Further, the plurality of balls 422 are held by a holder (not shown) so as to keep the interval in the circumferential direction constant.

  Such a wave generator 4 changes the direction of the cam portion 412 (the direction of the long axis La) as the cam 41 rotates about the axis a, and accordingly, the outer ring 423 also deforms, and the inner teeth The meshing positions of the gear 2 and the external gear 3 are moved in the circumferential direction. At this time, since the inner ring 421 is fixedly installed on the outer peripheral surface of the cam portion 412, the deformation state does not change.

Thus, the wave generator 4 has the elliptical outer peripheral surface 424 that contacts the inner peripheral surface 311 of the external gear 3. Here, as shown in FIG. 5, the length of the outer peripheral surface 424 in the major axis La direction is α [mm], and the length of the outer peripheral surface 424 in the minor axis Lb direction is β [mm]. As shown in FIG. 3, the angle formed by the straight line b and the axis a (rotation axis) in a cross-sectional view cut along a plane including the axis a (rotation axis) is δ [degrees], and the bottom portion 32 in the direction along the axis a ( When the distance between the mounting portion) and the center C of the tooth width of the internal gear 2 is L [mm]
atan ((α−β) / 4L) −0.6 ≦ δ ≦ atan ((α−β) / 4L) +0.6
It is preferable to satisfy the following relationship. Thereby, the meshing length of the internal gear 2 and the external gear 3 can be lengthened. Furthermore, when the relative position of the internal gear 2 and the external gear 3 in the direction along the axis a is changed, the change in the meshing length between the internal gear 2 and the external gear 3 can be reduced. .

  In addition, when the inclination angle (taper angle) of the body portion 31 with respect to the axis a when the external gear 3 is cut along a plane including the axis a and the long axis La is θ, θ = atan ((α−β) / 4L) is satisfied. In FIG. 5, the natural state of the inner peripheral surface 311 of the external gear 3 (the state where the wave generator 4 is not attached and no external force is applied) is indicated by a chain line. The diameter of the inner peripheral surface 311 in the natural state is (α + β) / 2.

  Further, the angle δ formed by the straight line b and the axis a (rotation axis) in a cross-sectional view cut along a plane including the axis a (rotation axis) is not particularly limited as long as it is greater than 0 degrees, but is not limited to 0.01 It is preferably in the range of 0.6 degrees or less, more preferably in the range of 0.01 degrees or more and 0.3 degrees or less, and in the range of 0.1 degrees or more and 0.3 degrees or less. More preferably. Thereby, the relative position of the internal gear 2 and the external gear 3 in the direction along the axis a can be easily and accurately changed. For example, when the tooth width of the internal gear 2 is 5 mm and the angle δ is in the range of 0.01 degrees or more and 0.6 degrees or less, along the axis a between the internal gear 2 and the external gear 3. It is possible to adjust the meshing dimension of both gears within a range of about 0.2 μm to 10 μm by changing the relative position in the direction of 1 mm. Therefore, in this case, the thickness of the spacer 7 may be in the range of about 0.2 μm to 10 μm.

  On the other hand, if the angle δ is too small, the width of the necessary adjustment such as the tooth contact strength of both gears must be increased unless the dimension of the internal gear 2 and the external gear 3 in the direction along the axis a is increased. It is difficult to ensure. On the other hand, if the angle δ is too large, it is difficult to increase the meshing length between the internal gear 2 and the external gear 3, and the durability of the gear device 1 tends to decrease.

  As described above, the gear device 1 has the internal gear 2 and the flexibility of being partially meshed with the internal gear 2 and rotating relative to the internal gear 2 around the axis a (rotation axis). An external gear 3 having a wave generator 4 that contacts the inner peripheral surface 311 of the external gear 3 and moves the meshing position of the internal gear 2 and the external gear 3 in the circumferential direction around the axis a. Have.

  And the virtual straight line b which extended the tooth trace of the internal gear 2 cross | intersects the axis line a in the position P by the cross sectional view cut | disconnected by the plane containing the axis line a (rotation axis). Thereby, by adjusting the relative position of the internal gear 2 and the external gear 3 in the direction along the axis a, the tooth contact strength between the internal gear 2 and the external gear 3 is adjusted. Can do. Therefore, even if the internal gear 2 or the external gear 3 has a dimensional variation, a desired tooth contact strength between the internal gear 2 and the external gear 3 can be obtained. Accordingly, it is not necessary to excessively increase the dimensional accuracy of the internal gear 2 and the external gear 3, and as a result, the cost of the gear device 1 can be reduced. Note that the straight line b is a straight line obtained by extending the root or tip of the internal tooth 23.

  Here, the external gear 3 has a cylindrical barrel portion 31 with one end portion (right end portion in FIG. 4) opened, and a radial direction from the other end portion (left end portion in FIG. 4) of the barrel portion 31. And a bottom portion 32 that is an attachment portion extending radially inward in the present embodiment, and the body portion 31 has external teeth 33 that engage with the internal gear 2 around the axis line a. In this embodiment, the position P where the straight line b intersects the axis a (rotation axis) is a center C of the tooth width of the internal gear 2 in a cross-sectional view cut along a plane including the axis a (rotation axis). Is also on the bottom 32 side (the other end side).

  Thus, since the position P is on the bottom 32 side of the center C of the tooth width of the internal gear 2, the internal teeth 23 of the internal gear 2 and the external teeth 33 of the external gear 3 are engaged with each other. In this case, it is inclined to the same side with respect to the axis a. Therefore, the meshing length between the internal gear 2 and the external gear 3 can be increased. Further, when the internal teeth 23 of the internal gear 2 and the external teeth 33 of the external gear 3 are inclined to the same side with respect to the axis line a in these meshing portions, in the case shown in the second embodiment to be described later. In comparison, when the relative position of the internal gear 2 and the external gear 3 in the direction along the axis a is changed, the change in the meshing length between the internal gear 2 and the external gear 3 can be reduced. it can.

  On the other hand, as in the conventional gear device 1X shown in FIG. 7, the direction of the internal teeth 23X of the internal gear 2X, that is, the virtual straight line b ′ extending from the root of the internal teeth 23X is parallel to the axis a. In some cases, the strength of contact between the internal gear 2 and the external gear 3 is determined by the dimensional accuracy of the internal gear 2, the external gear 3, and the wave generator 4. Therefore, in this case, in order to realize a meshing state such as a desired tooth contact strength between the internal gear 2 and the external gear 3, the dimensional accuracy of the internal gear 2, the external gear 3 and the wave generator 4 is increased. Therefore, it is necessary to increase the cost of the gear device 1X. In addition, since the tooth line direction of the internal teeth 23X of the internal gear 2X is parallel to the axis line a, even if the relative position in the direction along the axis line a between the internal gear 2X and the external gear 3 is changed, The tooth contact strength between the tooth gear 2X and the external gear 3 is basically the same.

Second Embodiment
FIG. 8 is a cross-sectional view (a view cut along a plane including the axis a) schematically showing a gear device according to the second embodiment of the present invention.

  The present embodiment is the same as the first embodiment described above except that the configuration and attachment of the internal gear are different. In the following description, the present embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted. Moreover, in FIG. 8, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above.

  A gear device 1A shown in FIG. 8 has an internal gear 2A and a flexibility that partially meshes with the internal gear 2A and relatively rotates about an axis a (rotation axis) with respect to the internal gear 2A. An external gear 3 and a wave generator 4 that contacts the inner peripheral surface 311 of the external gear 3 and moves the meshing position of the internal gear 2 and the external gear 3 in the circumferential direction around the axis a. .

  In the present embodiment, the tooth line direction of the internal gear 2A is inclined with respect to the axis a so that the inner diameter of the internal gear 2A decreases from the left side to the right side in FIG. Here, the external gear 3 has a cylindrical barrel portion 31 with one end portion (right end portion in FIG. 8) opened, and a radial direction from the other end portion (left end portion in FIG. 8) of the barrel portion 31. And a bottom portion 32 that is an attachment portion extending radially inward in the present embodiment, and the body portion 31 has external teeth 33 that engage with the internal gear 2 around the axis line a. Then, in a cross-sectional view cut along a plane including the axis a (rotation axis), the position P where the straight line b intersects the axis a is opposite to the bottom 32 from the center C of the tooth width of the internal gear 2A (one end). Part side). Accordingly, as shown in FIG. 8, when the member 6A for attaching the internal gear 2A is disposed on the side opposite to the bottom 32 with respect to the internal gear 2A, the axis a between the internal gear 2A and the external gear 3 The relative position in the direction along can be easily changed.

  The internal gear 2 </ b> A is connected to the member 6 </ b> A via the spacer 7, and the member 6 </ b> A is the base 110 or a member connected (fixed) to the base 110.

  It is preferable that the external teeth 33 of the external gear 3 have a portion that is inclined with respect to the axis line a on the same side as the tooth line direction of the internal teeth 23 in the meshing portion with the internal teeth 23 of the internal gear 2A. Thereby, the meshing length of 2 A of internal gears and the external gear 3 can be lengthened.

  Also by the second embodiment as described above, the same effect as that of the first embodiment described above can be exhibited.

  The robot and gear device of the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part is an arbitrary configuration having the same function. Can be substituted. In addition, any other component may be added to the present invention.

  In the above-described embodiment, the horizontal articulated robot has been described. However, the robot of the present invention is not limited to this, for example, the number of joints of the robot is arbitrary, and can be applied to a vertical articulated robot. It is.

  In the embodiment described above, the case where the external gear included in the gear device has a cup shape (bottomed cylindrical shape) has been described as an example. However, the present invention is not limited to this. For example, the external gear has a hat shape (with a collar). (Cylindrical) may be formed. When the external gear has a hat shape, the external gear has a flange portion extending radially outward from the other end portion of the body portion as an attachment portion.

DESCRIPTION OF SYMBOLS 1 ... Gear apparatus, 1A ... Gear apparatus, 1X ... Gear apparatus, 2 ... Internal gear, 2A ... Internal gear, 2X ... Internal gear, 3 ... External gear, 4 ... Wave generator, 6 ... Member, 6A ... member, 7 ... spacer, 23 ... internal teeth, 23X ... internal teeth, 31 ... trunk, 32 ... bottom, 33 ... external teeth, 41 ... cam, 42 ... bearing, 100 ... robot, 110 ... base, 111 ... 120, 1st arm, 121 ... 1st arm, 130 ... 2nd arm, 140 ... Working head, 141 ... Spline shaft, 150 ... End effector, 160 ... part, 170 ... 1st drive part, 171 ... Motor , 190 ... Control device, 311 ... Inner peripheral surface, 411 ... Shaft portion, 412 ... Cam portion, 421 ... Inner ring, 422 ... Ball, 423 ... Outer ring, 424 ... Outer peripheral surface, C ... Center, J1 ... First shaft, J2 ... second axis, J3 ... axis, La ... long axis, Lb Minor axis, a ... axis, b ... straight, b '... linear, P ... position, [delta] ... angle

Claims (7)

A first member;
A second member that rotates relative to the first member;
A gear device that transmits a driving force for rotating the second member relative to the first member from one side to the other side of the first member and the second member;
The gear device is
An internal gear,
A flexible external gear that partially meshes with the internal gear and rotates relative to the internal gear around a rotation axis;
A wave generator that contacts an inner peripheral surface of the external gear, and moves a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis;
One of the internal gear, the external gear and the wave generator is connected to the first member, and the other is connected to the second member.
A robot characterized in that a virtual straight line obtained by extending a tooth trace of the internal gear intersects the rotation axis in a cross-sectional view cut along a plane including the rotation axis. The external gear is
A cylindrical body having external teeth meshing with the internal gear, centered on the rotation shaft, and having one end opened;
An attachment portion extending in a radial direction from the other end portion of the body portion, and
2. The robot according to claim 1, wherein, in the cross-sectional view, the position where the straight line and the rotation axis intersect is located on the one end side with respect to the center of the tooth width of the internal gear. The external gear is
A cylindrical body having external teeth meshing with the internal gear, centered on the rotation shaft, and having one end opened;
An attachment portion extending in a radial direction from the other end portion of the body portion, and
2. The robot according to claim 1, wherein, in the cross-sectional view, the position where the straight line and the rotation axis intersect is located on the other end side with respect to the center of the tooth width of the internal gear. The wave generator is
It has an elliptical outer peripheral surface that contacts the inner peripheral surface of the external gear,
The length of the outer peripheral surface in the major axis direction is α [mm], the length of the outer peripheral surface in the minor axis direction is β [mm], and the angle formed by the straight line and the rotation axis in the sectional view. Is δ [degrees], and the distance between the mounting portion and the center of the tooth width of the internal gear in the direction along the rotation axis is L [mm]
atan ((α−β) / 4L) −0.6 ≦ δ ≦ atan ((α−β) / 4L) +0.6
The robot according to claim 2 or 3, satisfying the following relationship. The internal gear is connected to the first member;
The robot according to any one of claims 1 to 4, wherein a spacer is disposed between the internal gear and the first member.   The robot according to any one of claims 1 to 5, wherein an angle formed by the straight line and the rotation axis in the cross-sectional view is in a range of 0.01 degrees to 0.6 degrees. An internal gear,
A flexible external gear that partially meshes with the internal gear and rotates relative to the internal gear around a rotation axis;
A wave generator that contacts an inner peripheral surface of the external gear, and moves a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis;
The internal gear is a gear device characterized in that an imaginary straight line obtained by extending a tooth line of the internal gear intersects the rotation shaft in a sectional view cut along a plane including the rotation shaft.

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